1. Field of the Invention
The present invention relates to a drum-type washing machine. More specifically, the present invention relates to a drum-type washing machine in which a rotation shaft of a motor is coupled to a rotation shaft of a drum via a reduction mechanism which includes a plurality of power transmission elements.
2. Description of the Prior Art
In such a kind of drum-type washing machine, a horizontal shaft type drum is rotatably supported within an outer tub which is supported in a frame. By coupling a rotation shaft of the drum and a rotation shaft of a motor to each other via a reduction mechanism, the drum is rotated, and the wash entered in the drum from an opening which is formed on a peripheral surface of the drum is washed or dried. In such a drum-type washing machine, in order to make the entry of the wash into the drum and the taking-out of the wash from the drum easy, it is necessary to fix the rotation of the drum in a state where the above described opening is stopped at a predetermined position.
One example of a prior art associated with such a drum lock mechanism is disclosed in Japanese Patent Laying-Open Gazette No. 63-311991 (D06F 21/04) laid-open on Dec. 20, 1988. In this prior art, a disk having a recess is secured to one end of a rotation shaft which rotatably supports a drum, and when the recess is engaged with a pin the drum is locked at a constant position.
In the above described prior art, since the drum is locked by means of the engagement of the recess of the disk which is directly fixed to the rotation shaft of the drum and the pin, an error of the recess in position directly generates deviation of a drum lock position. Therefore, in order to eliminate the deviation of the drum lock position, it is necessary to manufacture the disk, recess thereof, pin and etc. with higher precision. In addition, since the rotation shaft of the drum and the disk is directly coupled to each other, in a case where an eccentric load of the wash within the drum is large, the recess of the disk and the pin are affected by a large torque due to the eccentric load, and therefore, it is necessary to make strength of these elements large. Thus, in the prior art, a drum-type washing machine results in a high cost.